From 9e47480e94c86fef6f50bf40dde4db766eeeddee Mon Sep 17 00:00:00 2001
From: Conrad Meyer <cem@FreeBSD.org>
Date: Tue, 3 Nov 2020 19:50:42 +0000
Subject: [PATCH] linux(4): Improve netlink diagnostics

Add some missing netlink_family definitions and produce vaguely
human-readable error messages for those definitions, like we used to do for
just ROUTE and KOBJECT_UEVENTS.

Additionally, if we know it's a netfilter socket but didn't find it in the
table, fall back to printing that instead of the generic handler ("socket
domain 16, ...").

No change to the emulator correctness, just mildly improved diagnostics for
gaps.
---
 sys/compat/linux/linux.h        | 10 +++++--
 sys/compat/linux/linux_socket.c | 48 ++++++++++++++++++++++-----------
 2 files changed, 41 insertions(+), 17 deletions(-)

diff --git a/sys/compat/linux/linux.h b/sys/compat/linux/linux.h
index 947c8e58065f..48217959951c 100644
--- a/sys/compat/linux/linux.h
+++ b/sys/compat/linux/linux.h
@@ -60,8 +60,14 @@ struct l_sockaddr {
 #define	LINUX_AF_INET6		10
 #define	LINUX_AF_NETLINK	16
 
-#define	LINUX_NETLINK_ROUTE	0
-#define	LINUX_NETLINK_UEVENT	15
+#define	LINUX_NETLINK_ROUTE		0
+#define	LINUX_NETLINK_SOCK_DIAG		4
+#define	LINUX_NETLINK_NFLOG		5
+#define	LINUX_NETLINK_SELINUX		7
+#define	LINUX_NETLINK_AUDIT		9
+#define	LINUX_NETLINK_FIB_LOOKUP	10
+#define	LINUX_NETLINK_NETFILTER		12
+#define	LINUX_NETLINK_KOBJECT_UEVENT	15
 
 /*
  * net device flags
diff --git a/sys/compat/linux/linux_socket.c b/sys/compat/linux/linux_socket.c
index 2ac96dd6c92e..e526a8844198 100644
--- a/sys/compat/linux/linux_socket.c
+++ b/sys/compat/linux/linux_socket.c
@@ -502,6 +502,17 @@ linux_sendto_hdrincl(struct thread *td, struct linux_sendto_args *linux_args)
 	return (error);
 }
 
+static const char *linux_netlink_names[] = {
+	[LINUX_NETLINK_ROUTE] = "ROUTE",
+	[LINUX_NETLINK_SOCK_DIAG] = "SOCK_DIAG",
+	[LINUX_NETLINK_NFLOG] = "NFLOG",
+	[LINUX_NETLINK_SELINUX] = "SELINUX",
+	[LINUX_NETLINK_AUDIT] = "AUDIT",
+	[LINUX_NETLINK_FIB_LOOKUP] = "FIB_LOOKUP",
+	[LINUX_NETLINK_NETFILTER] = "NETFILTER",
+	[LINUX_NETLINK_KOBJECT_UEVENT] = "KOBJECT_UEVENT",
+};
+
 int
 linux_socket(struct thread *td, struct linux_socket_args *args)
 {
@@ -516,22 +527,29 @@ linux_socket(struct thread *td, struct linux_socket_args *args)
 		return (retval_socket);
 	domain = linux_to_bsd_domain(args->domain);
 	if (domain == -1) {
-		if (args->domain == LINUX_AF_NETLINK &&
-		    args->protocol == LINUX_NETLINK_ROUTE) {
-			linux_msg(curthread,
-			    "unsupported socket(AF_NETLINK, %d, NETLINK_ROUTE)", type);
-			return (EAFNOSUPPORT);
+		/* Mask off SOCK_NONBLOCK / CLOEXEC for error messages. */
+		type = args->type & LINUX_SOCK_TYPE_MASK;
+		if (args->domain == LINUX_AF_NETLINK) {
+			const char *nl_name;
+
+			if (args->protocol >= 0 &&
+			    args->protocol < nitems(linux_netlink_names))
+				nl_name = linux_netlink_names[args->protocol];
+			else
+				nl_name = NULL;
+			if (nl_name != NULL)
+				linux_msg(curthread,
+				    "unsupported socket(AF_NETLINK, %d, "
+				    "NETLINK_%s)", type, nl_name);
+			else
+				linux_msg(curthread,
+				    "unsupported socket(AF_NETLINK, %d, %d)",
+				    type, args->protocol);
+		} else {
+			linux_msg(curthread, "unsupported socket domain %d, "
+			    "type %d, protocol %d", args->domain, type,
+			    args->protocol);
 		}
-		    
-		if (args->domain == LINUX_AF_NETLINK &&
-		    args->protocol == LINUX_NETLINK_UEVENT) {
-			linux_msg(curthread,
-			    "unsupported socket(AF_NETLINK, %d, NETLINK_UEVENT)", type);
-			return (EAFNOSUPPORT);
-		}
-	
-		linux_msg(curthread, "unsupported socket domain %d, type %d, protocol %d",
-		    args->domain, args->type & LINUX_SOCK_TYPE_MASK, args->protocol);
 		return (EAFNOSUPPORT);
 	}